Linear Algebra Examples

$y = \frac{3 x}{4}$ , $x = 2$ , $y = 1$ , $y = 2 x$

Step 1

Subtract $\frac{3 x}{4}$ from both sides of the equation.

$y - \frac{3 x}{4} = 0, x = 2, y = 1, y = 2 x$

Step 2

Subtract $2 x$ from both sides of the equation.

$y - \frac{3 x}{4} = 0, x = 2, y = 1, y - 2 x = 0$

Step 3

Write the system of equations in matrix form.

$[\begin{array}{c} - \frac{3}{4} & 1 & 0 \\ 1 & 0 & 2 \\ 0 & 1 & 1 \\ - 2 & 1 & 0 \end{array}]$

Step 4

Find the reduced row echelon form.

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Step 4.1

Multiply each element of $R_{1}$ by $- \frac{4}{3}$ to make the entry at $1, 1$ a $1$ .

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Step 4.1.1

Multiply each element of $R_{1}$ by $- \frac{4}{3}$ to make the entry at $1, 1$ a $1$ .

$[\begin{array}{c} - \frac{4}{3} (- \frac{3}{4}) & - \frac{4}{3} \cdot 1 & - \frac{4}{3} \cdot 0 \\ 1 & 0 & 2 \\ 0 & 1 & 1 \\ - 2 & 1 & 0 \end{array}]$

Step 4.1.2

Simplify $R_{1}$ .

$[\begin{array}{c} 1 & - \frac{4}{3} & 0 \\ 1 & 0 & 2 \\ 0 & 1 & 1 \\ - 2 & 1 & 0 \end{array}]$

Step 4.2

Perform the row operation $R_{2} = R_{2} - R_{1}$ to make the entry at $2, 1$ a $0$ .

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Step 4.2.1

Perform the row operation $R_{2} = R_{2} - R_{1}$ to make the entry at $2, 1$ a $0$ .

$[\begin{array}{c} 1 & - \frac{4}{3} & 0 \\ 1 - 1 & 0 + \frac{4}{3} & 2 - 0 \\ 0 & 1 & 1 \\ - 2 & 1 & 0 \end{array}]$

Step 4.2.2

Simplify $R_{2}$ .

$[\begin{array}{c} 1 & - \frac{4}{3} & 0 \\ 0 & \frac{4}{3} & 2 \\ 0 & 1 & 1 \\ - 2 & 1 & 0 \end{array}]$

Step 4.3

Perform the row operation $R_{4} = R_{4} + 2 R_{1}$ to make the entry at $4, 1$ a $0$ .

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Step 4.3.1

Perform the row operation $R_{4} = R_{4} + 2 R_{1}$ to make the entry at $4, 1$ a $0$ .

$[\begin{array}{c} 1 & - \frac{4}{3} & 0 \\ 0 & \frac{4}{3} & 2 \\ 0 & 1 & 1 \\ - 2 + 2 \cdot 1 & 1 + 2 (- \frac{4}{3}) & 0 + 2 \cdot 0 \end{array}]$

Step 4.3.2

Simplify $R_{4}$ .

$[\begin{array}{c} 1 & - \frac{4}{3} & 0 \\ 0 & \frac{4}{3} & 2 \\ 0 & 1 & 1 \\ 0 & - \frac{5}{3} & 0 \end{array}]$

Step 4.4

Multiply each element of $R_{2}$ by $\frac{3}{4}$ to make the entry at $2, 2$ a $1$ .

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Step 4.4.1

Multiply each element of $R_{2}$ by $\frac{3}{4}$ to make the entry at $2, 2$ a $1$ .

$[\begin{array}{c} 1 & - \frac{4}{3} & 0 \\ \frac{3}{4} \cdot 0 & \frac{3}{4} \cdot \frac{4}{3} & \frac{3}{4} \cdot 2 \\ 0 & 1 & 1 \\ 0 & - \frac{5}{3} & 0 \end{array}]$

Step 4.4.2

Simplify $R_{2}$ .

$[\begin{array}{c} 1 & - \frac{4}{3} & 0 \\ 0 & 1 & \frac{3}{2} \\ 0 & 1 & 1 \\ 0 & - \frac{5}{3} & 0 \end{array}]$

Step 4.5

Perform the row operation $R_{3} = R_{3} - R_{2}$ to make the entry at $3, 2$ a $0$ .

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Step 4.5.1

Perform the row operation $R_{3} = R_{3} - R_{2}$ to make the entry at $3, 2$ a $0$ .

$[\begin{array}{c} 1 & - \frac{4}{3} & 0 \\ 0 & 1 & \frac{3}{2} \\ 0 - 0 & 1 - 1 & 1 - \frac{3}{2} \\ 0 & - \frac{5}{3} & 0 \end{array}]$

Step 4.5.2

Simplify $R_{3}$ .

$[\begin{array}{c} 1 & - \frac{4}{3} & 0 \\ 0 & 1 & \frac{3}{2} \\ 0 & 0 & - \frac{1}{2} \\ 0 & - \frac{5}{3} & 0 \end{array}]$

Step 4.6

Perform the row operation $R_{4} = R_{4} + \frac{5}{3} R_{2}$ to make the entry at $4, 2$ a $0$ .

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Step 4.6.1

Perform the row operation $R_{4} = R_{4} + \frac{5}{3} R_{2}$ to make the entry at $4, 2$ a $0$ .

$[\begin{array}{c} 1 & - \frac{4}{3} & 0 \\ 0 & 1 & \frac{3}{2} \\ 0 & 0 & - \frac{1}{2} \\ 0 + \frac{5}{3} \cdot 0 & - \frac{5}{3} + \frac{5}{3} \cdot 1 & 0 + \frac{5}{3} \cdot \frac{3}{2} \end{array}]$

Step 4.6.2

Simplify $R_{4}$ .

$[\begin{array}{c} 1 & - \frac{4}{3} & 0 \\ 0 & 1 & \frac{3}{2} \\ 0 & 0 & - \frac{1}{2} \\ 0 & 0 & \frac{5}{2} \end{array}]$

Step 4.7

Multiply each element of $R_{3}$ by $- 2$ to make the entry at $3, 3$ a $1$ .

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Step 4.7.1

Multiply each element of $R_{3}$ by $- 2$ to make the entry at $3, 3$ a $1$ .

$[\begin{array}{c} 1 & - \frac{4}{3} & 0 \\ 0 & 1 & \frac{3}{2} \\ - 2 \cdot 0 & - 2 \cdot 0 & - 2 (- \frac{1}{2}) \\ 0 & 0 & \frac{5}{2} \end{array}]$

Step 4.7.2

Simplify $R_{3}$ .

$[\begin{array}{c} 1 & - \frac{4}{3} & 0 \\ 0 & 1 & \frac{3}{2} \\ 0 & 0 & 1 \\ 0 & 0 & \frac{5}{2} \end{array}]$

Step 4.8

Perform the row operation $R_{4} = R_{4} - \frac{5}{2} R_{3}$ to make the entry at $4, 3$ a $0$ .

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Step 4.8.1

Perform the row operation $R_{4} = R_{4} - \frac{5}{2} R_{3}$ to make the entry at $4, 3$ a $0$ .

$[\begin{array}{c} 1 & - \frac{4}{3} & 0 \\ 0 & 1 & \frac{3}{2} \\ 0 & 0 & 1 \\ 0 - \frac{5}{2} \cdot 0 & 0 - \frac{5}{2} \cdot 0 & \frac{5}{2} - \frac{5}{2} \cdot 1 \end{array}]$

Step 4.8.2

Simplify $R_{4}$ .

$[\begin{array}{c} 1 & - \frac{4}{3} & 0 \\ 0 & 1 & \frac{3}{2} \\ 0 & 0 & 1 \\ 0 & 0 & 0 \end{array}]$

Step 4.9

Perform the row operation $R_{2} = R_{2} - \frac{3}{2} R_{3}$ to make the entry at $2, 3$ a $0$ .

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Step 4.9.1

Perform the row operation $R_{2} = R_{2} - \frac{3}{2} R_{3}$ to make the entry at $2, 3$ a $0$ .

$[\begin{array}{c} 1 & - \frac{4}{3} & 0 \\ 0 - \frac{3}{2} \cdot 0 & 1 - \frac{3}{2} \cdot 0 & \frac{3}{2} - \frac{3}{2} \cdot 1 \\ 0 & 0 & 1 \\ 0 & 0 & 0 \end{array}]$

Step 4.9.2

Simplify $R_{2}$ .

$[\begin{array}{c} 1 & - \frac{4}{3} & 0 \\ 0 & 1 & 0 \\ 0 & 0 & 1 \\ 0 & 0 & 0 \end{array}]$

Step 4.10

Perform the row operation $R_{1} = R_{1} + \frac{4}{3} R_{2}$ to make the entry at $1, 2$ a $0$ .

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Step 4.10.1

Perform the row operation $R_{1} = R_{1} + \frac{4}{3} R_{2}$ to make the entry at $1, 2$ a $0$ .

$[\begin{array}{c} 1 + \frac{4}{3} \cdot 0 & - \frac{4}{3} + \frac{4}{3} \cdot 1 & 0 + \frac{4}{3} \cdot 0 \\ 0 & 1 & 0 \\ 0 & 0 & 1 \\ 0 & 0 & 0 \end{array}]$

Step 4.10.2

Simplify $R_{1}$ .

$[\begin{array}{c} 1 & 0 & 0 \\ 0 & 1 & 0 \\ 0 & 0 & 1 \\ 0 & 0 & 0 \end{array}]$

Step 5

Use the result matrix to declare the final solutions to the system of equations.

$x = 0$

$y = 0$

$0 = 1$

Step 6

Since $0 \neq 1$ , there are no solutions.

No solution